#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
const ll mod = 1e9 + 7;
ll dp[100][100];
ll flag[100][100];

ll f(int x, int y) {
    if (dp[x][y])return dp[x][y];
    if (x == 1 || y == 1)return dp[x][y] = 1;

    ll t = 0;
    if (x - 1 != y)t += f(x - 1, y);
    if (x != y - 1)t += f(x, y - 1);
    return dp[x][y] = t;
}

int main() {
    int n;
    cin >> n;
    cout << f(n + 1, n + 1) << endl;

    //cout<<dp[1][1];

    return 0;
}
